This disclosure directs itself, in one arrangement, to a blend and configuration control for use with a string instrument having pickup transducers and permits blending the output of a parallel configuration of a pair, or pairs, of pickup transducers and reversibly switching between parallel and series configurations without disturbing the blend setting of the parallel configuration. Further, the blend and configuration control for a string instrument provides parallel blending of the output of a pair of pickup transducers that ranges from selection of the output of one of the pickup transducers alone, through a mix of output levels of the two pickup transducers, to selection of the output of the other of the pickup transducers alone. More in particular, the disclosure is directed to a blend and configuration control for a string instrument that includes a pair of pickup transducers disposed on the string instrument for producing voltages responsive to vibration of at least one string of the string instrument and a pair of potentiometers that are coupled thereto for blending the output of the pickup transducers while in a parallel configuration and a switch for simply and instantaneously switching the configuration of the pickup transducers to a series configuration.
In another arrangement, this disclosure is directed to a blend and configuration control for a string instrument having pickup transducers that permits blending the output of a series configuration of the pickup transducers and switching between one or the other of a pair or pairs of the pickup transducers. In the other arrangement, the pair of potentiometers are coupled to a pair of output terminals and respectively to the pickup transducers, while the displaceable contacts of the potentiometers are electrically connected together for selective operative coupling of the pickup transducers in series between the output terminals, or one of the pickup transducers coupled to the output terminals, responsive to a position of the displaceable contacts of the pair of potentiometers, or the other of the pickup transducers coupled to the output terminals, responsive to another position of the displaceable contacts of the pair of potentiometers.
Electric string instruments, such as electric guitars, electric bases, electric violins, etc., use at least one pickup transducer to convert the vibration of instrument's strings into electrical impulses. The most commonly used pickups use the principle of direct electromagnetic induction. The signal generated by the pickup is of insufficient strength to directly drive an audio transducer, such as a loudspeaker, so it must be amplified prior to being input to the audio transducer.
Because of their natural inductive qualities, all magnetic pickups tend to pick up ambient electromagnetic interference (EMI) from electrical power wiring in the vicinity, such as the wiring in a building. The EMI from a 50 or 60 Hz power system can result in a noticeable “hum” in the amplified audio output from the audio transducer, particularly with poorly shielded single-coil pickups. Double-coil “Humbucker” pickups were invented as a way to overcoming the problem of unwanted ambient hum sounds. Humbucker pickups have two coils arranged to be of opposite magnetic and electric polarity so as to produce a differential signal. As ambient electromagnetic noise affects both coils equally and since they are poled oppositely, the noise signals induced in the two coils are cancelled out. The two coils of a Humbucker are often wired in series to give a fuller and stronger sound.
It is very common to utilize a pair of pickup transducers on a modern electric string instrument, one located in proximity to the bridge of the instrument and the other in proximity to the neck of the instrument. While most single coil pickups are wired in parallel with each other, it is also possible to wire them in series, producing a fuller and stronger sound. The two coils of a Humbucker type pickup can be connected in parallel as well. This results in a brighter sound, since it passes higher frequency components of the sound that would otherwise be suppressed in the series arrangement, but it is at the cost of a lower output voltage, as with a single-coil pickup. However, in the parallel configuration, the pickup's hum-cancelling properties are still retained. Using a multiple pole, multiple throw switch, such as a double pole, double throw switch (DPDT) or double pole three position switch, it is known in the art to switch the coil configuration between series and parallel, and may also provide for a “coil cut” configuration (a single coil output).
Blend potentiometers, usually formed by two potentiometers ganged together to be rotated by a single shaft, allow blending together outputs of two pickup coils in varying degrees, not unlike a balance control provided in stereo equipment. Blend potentiometers, however, do not typically accomplish switching of the coil configuration. In one known prior art system disclosed in U.S. Pat. No. 4,423,654, a tone control formed with a pair of ganged rheostats is connected to the two coils of a Humbucker type pickup. The operation of this tone control provides a series coil configuration at one end of the rotation of the control and a parallel configuration at the opposing end of the rotation thereof. Of the two rheostats used, the resistance element of one is configured to have substantially zero resistance (zero ohms) between one end terminal and the midpoint of the resistance element's length and thereafter increase linearly, while the other rheostat has a resistance that increases logarithmically along its length. Due to the logarithmic taper of the resistance element, from the one end of the travel of the control that provides a series configuration of the coils to and including the midpoint thereof, the series configuration is maintained, changing only the high frequency attenuation included in the control.
Thus, there is a need for a blend and configuration control that provides a parallel blend, series selectable configuration control for use by a musician. A need for the ability of the musician to select the output of either the neck pickup transducer or bridge pickup transducer alone, while in the parallel configuration. Also, a need for the ability of the musician to leave the knob of the blend potentiometers at any selected parallel blending of the outputs of the neck and bridge pickup transducers and simply, and instantaneously switch to the completely different configuration of the two pickup transducers in series. Thus, with one touch of the switch the musician is able to change the volume and sound of the instrument. The higher voltage produced by the series configuration has the effect of providing increased volume. If the type of pickup transducers utilizes electromagnetic induction to sense the vibration of the instrument's strings, then the pickups have coils that offer higher impedance to higher frequencies than to lower frequencies. Hence coupling the pickup coils in series has the effect of lowering the voltages of the high frequency components of the sound, providing a more mellow sound output while at the same time increasing the volume of the overall sound output.
There is also a need for a blend and configuration control that provides a series blending of the output of a pair of the neck and bridge pickup transducers, where one or the other can dominate, yet allow the musician to select the output of either the neck pickup transducer or bridge pickup transducer alone.